Italian Language/use of preposition"da"

Can you please tell me why the preposition “da” is used in the following sentence:

“La popolazione del Belgio è composta da Fiamminghi e Valloni”

I was wondering why the preposition “di” is not used (instead of “da”) to form the indirect object as in “di Fiamminghi e Valloni”

Thank you very much.

Sincerely,

Rich

AnswerDear Rich,

actually the adjective “composto” can be followed by either “di” or “da”, so that we can say “La popolazione del Belgio è composta da Fiamminghi e Valloni” as well as “La popolazione del Belgio è composta di Fiamminghi e Valloni”, although “da” is better than “di” in this context.